1. Field of the Invention
This invention relates to a magnetic tape apparatus for recording, reproducing and erasing information with respect to a magnetic tape.
2. Description of the Related Art
Japanese Patent Unexamined Publication No. Sho. 61-137255 and Japanese Patent Unexamined Publication No. Hei. 7-14250 describe the technology of magnetic tape apparatus of the type mentioned above and one example of the conventional magnetic tape apparatus will be described with reference to FIGS. 12 to 15 hereinafter. A cradle 3 for supporting a tape cassette T is movably disposed on a chassis 1 between a pair of parallel guide plates 2 uprightly provided with a predetermined space held therebetween. Also provided is a cassette loading mechanism 7 for interlocking the cradle 3 with a driving means 4 via a moving rod 5 reciprocally moved by the driving means 4 and a cradle interlocking mechanism 6, and a tape loading mechanism 8 for drawing a magnetic tape t out of the tape cassette T.
The cradle 3 has a bottom plate portion 3a, and a pair of side plate portions 3b uprightly provided on the respective side edges of the bottom plate portion 3a. Further, a support rod 3c projected from each side plate portion 3b is movably inserted in a substantially L-shaped guide groove 9 formed in each guide plate 2, and a leaf spring 10 for pressing down the surface of the tape cassette T is also provided at the upper end of each side plate portion 3b. 
The driving means 4 has a worm gear 14 rotated by a driving motor 12 via a belt transmission mechanism 13 fixed via a coupling rod 11a to the chassis 1 over a board 1, a circular cam plate 16 that is rotatably supported via a support shaft 15 over the chassis 1, with a toothed portion 16a that is formed on the outer periphery of the cam plate 16 and engages with the worm gear 14, and a rocking plate 19 whose one end is pivotally supported by a pivotal shaft 17 over the chassis 1 and whose cam pin 18 projected from the central portion of the rocking plate 19 is inserted in a spiral cam groove 16b of the cam plate 16, the other end thereof being coupled to the moving rod 5 with a pin. The cam plate 16 is then rotated forward and backward in directions a and b by actuating the driving motor 12 to reciprocate the rocking plate 19 via the cam pin 18 around the pivotal shaft 17 whereby to reciprocate the moving rod 5 in directions c and d.
The cradle interlocking mechanism 6 has a pair of pinion portions 23 rotatably and pivotally supported by the guide plate 2 via a support shaft 21, and projected portions 24 provided for the respective pinion portions 23. Each of the support rods 3c is fitted in a slot 25 running through the projected portion 24, and one of the pinion portions 23 is made to engage with a rack portion 22 formed on the moving rod 5. Both the pinion portions 23 are interlocked and integrally coupled together by making a pair of fan-like gears 27 engage with the respective pinion portions 23, the pair of fan-like gears 27 being secured to the respective ends of a rotary shaft 26 rotatably supported by both the guide plates 2. Further, both the projected portions 24 are reciprocated around the support shaft 21 via the rack portion 22 and the pinion portions 23 by reciprocating the moving rod 5 in the directions c and d, whereby the cradle 3 can be reciprocated longitudinally in directions e and f.
The tape loading mechanism 8 has a pair of moving stands 32 each having guide posts 31 that are movable along a lateral pair of slots 30 formed with a head cylinder 29 held therebetween, a pair of fan-like gears 34 that are rotatably and pivotally supported by the chassis 1 via a pivotal shaft 33 and engage with each other, a pair of link mechanisms 35 for interlocking the fan-like gears 34 with the respective moving stands 32, and an interlocking rod 36 whose rack portion 36a formed in its one end portion engages with a pinion portion 37 formed integrally with the one fan-like gear 34. The other end portion of the interlocking rod 36 is interlocked with the cam plate 16 via a cam mechanism (not shown). The interlocking rod 36 is reciprocated in directions g and h by rotating the cam plate 16 forward and backward in the directions a and b, whereby each moving stand 32 can be reciprocated in directions i and j along the slot 30 via the rack portion 36a, the pinion portion 37, the fan-like gear 34 and the link mechanism 35.
In FIG. 12, reference numeral 39 denotes a full erase head; 40, an audio erase head; 41, an audio/control head; 42, a fixed tape guide post; 43, a capstan that is rotated by a capstan motor 43a; 44, a pinch roller for pressing the magnetic tape t against the capstan 43; 45, a tension post for applying tension to the magnetic tape t at the time of tape loading; and 46, pins for positioning the moving stands, pins 46 being projected from the chassis 1 opposite to the respective front ends of the slots 30.
A loading procedure will now be described. As shown in FIGS. 12 and 13, the cradle 3 is slightly moved backward when the cradle 3 in a forward standby state is loaded with the tape cassette T and its slight backward movement is detected by a detector (not shown). A detection signal from the detector causes the driving motor 12 to be driven, so that the cam plate 16 is rotated forward in the direction a via the belt transmission mechanism 13 and the like. Thus, the rocking plate 19 is pivoted around the pivotal shaft 17 because of the cam action of the cam pin 18 and the cam groove 16b whereby to move the moving rod 5 forward in the direction c and the cradle 3 is moved horizontally along the guide groove 9 backward in the direction e via the cradle interlocking mechanism 6 before being moved down. Then the tape cassette T is set in position (see FIG. 15) and the cassette loading is completed. Further, the interlocking rod 36 is moved forward in the direction g and each of the moving stands 32 is also moved forward in the direction i along the slot 30 via the rack portion 36a and the like. The magnetic tape t is drawn out of the tape cassette T by each guide post 31 before being wound on the head cylinder 29 (see FIG. 14) whereby to terminate the tape loading. Then the operation is switched to a reproduction mode, for example, by operating a mode switching lever (not shown) so as to reproduce the information recorded on the magnetic tape t.
With the conventional arrangement described above, although the rocking plate 19 is used to extend the moving distance of the cam pin 18 and to increase the outer diameter D of the cam plate 16 in accordance with the ratio of the distance r from the pivotal shaft 17 up to the cam pin 18 to the distance R from the pivotal shaft 17 up to the moving rod 5 to ensure the cassette loading and tape loading by increasing the moving strokes of the moving rod 5 and interlocking rod 36 as shown in FIG. 12, this may result in increasing not only the number of parts but also the production cost.
An object of the present invention in view of the foregoing shortcomings is to provide a magnetic tape apparatus that can be produced less costly with a smaller number of parts.
In order to accomplish the above object, according to a first aspect of the invention, there is provided a magnetic tape apparatus comprising: a cradle movably disposed on a chassis and used for supporting a tape cassette; and a cassette loading mechanism for interlocking the cradle with driving means via a moving rod which is reciprocated by the driving means, the driving means including a first pinion which is rotated forward and backward and a first rack integrally formed with the moving rod and made to engage with the first pinion, wherein when the driving means makes the moving rod move forward, the cradle is moved backward horizontally before being moved down, so that the tape cassette is set in a predetermined position on the chassis and wherein a magnetic tape is subsequently drawn out of the tape cassette by a tape loading mechanism.
According to a second aspect of the invention, there is provided a magnetic tape apparatus comprising: a cradle movably disposed on a chassis and used for supporting a tape cassette; and a cassette loading mechanism for interlocking the cradle with driving means via a moving rod which is reciprocated by the driving means, the driving means including a first pinion which is rotated forward and backward and a first rack integrally formed with the moving rod and made to engage with the first pinion, wherein the cradle is slightly moved backward when the cradle in a forward standby state is loaded with the tape cassette, wherein when the driving means makes the moving rod move forward upon detection of the slight backward movement of the cradle, the cradle is moved backward horizontally before being moved down, so that the tape cassette is set in a predetermined position on the chassis and wherein a magnetic tape is subsequently drawn out of the tape cassette by a tape loading mechanism.
According to a third aspect of the invention, there is provided a magnetic tape apparatus comprising a cradle movably disposed on a chassis and used for supporting a tape cassette, wherein the cradle is moved backward horizontally by a cassette loading mechanism before being moved down, so that the tape cassette on the cradle is set in a predetermined position on the chassis and wherein a magnetic tape is subsequently drawn out of the tape cassette by a tape loading mechanism, the tape loading mechanism comprising: an interlocking rod which is interlocked with a pair of moving stands with guide posts; a second rack integrally formed with the interlocking rod; and a second pinion capable of engaging with the second rack, wherein both the moving stands are moved via the interlocking rod by rotating the second pinion forward in such a state that the second rack has engaged with the second pinion, and the magnetic tape is drawn out of the tape cassette by each of the guide posts and wound on a head cylinder.